Leave the spark plugs along unless you're getting misfire codes. They are good for 100,000 miles. More likely a coil pack will die before the plugs.
Leave the E-brake alone also. Pretty much a sealed unit needing little if any maintenance other than a level check.
Fuel filter is quick and easy but you could hold off until 50,000 miles. It's on the driver's side frame rail in front evap canisters. You will need a special tool to release the fuel lines which cost's about $5.
Changing the hydraulic fluid in the jacks is a good, nice weather, Saturday project.
Leave the tires alone unless you see unusual wear patterns on the fronts. Then rotate and have the front end checked out and maybe aligned.
Regarding shocks ask Santa Claus for a set of Koni shocks.
Take a close look and the upper and lower radiator hoses and heater core hoses for potential replacement. Also the clamps.
Inspect the front suspension and steering gear grease seals. Pretty obvious when a seal is torn and needs to be replaced. I can't recall the part number for replacements but if you do a search in this forum you'll find a number for I think it was Spartan chassis seals that fit.
Check your rear axle. If you have a Dana 80 (11,000 lbs. rated) the rear cover on the differential is removable and makes a fluid change much easier. If you have to pump out the old oil first drive the coach to get the differential as warm as possible other wise getting the heavy oil out is difficult when cold.
You'll need about 3 qtrs. of DOT 3 brake fluid for a full flush. Get one of these - https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
and one of these - https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
. Will make job quick and easy. Check the rear brake pads also. Considering the weight distribution of an RV, heavy rear/light front, the rears can wear just as fast as the fronts unlike a car.
Do the drive belt. Another easy driveway job and good to know how to do it just incase you need to replace on the side of the road someday. Save the old belt just incase.
You may not need to grease the front axles but the only way to know is to disassemble the hubs to see if the bearings are seal or not.